1/*	$NetBSD: if_stf.c,v 1.109 2022/09/03 02:47:59 thorpej Exp $	*/
2/*	$KAME: if_stf.c,v 1.62 2001/06/07 22:32:16 itojun Exp $ */
3
4/*
5 * Copyright (C) 2000 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33/*
34 * 6to4 interface, based on RFC3056.
35 *
36 * 6to4 interface is NOT capable of link-layer (I mean, IPv4) multicasting.
37 * There is no address mapping defined from IPv6 multicast address to IPv4
38 * address.  Therefore, we do not have IFF_MULTICAST on the interface.
39 *
40 * Due to the lack of address mapping for link-local addresses, we cannot
41 * throw packets toward link-local addresses (fe80::x).  Also, we cannot throw
42 * packets to link-local multicast addresses (ff02::x).
43 *
44 * Here are interesting symptoms due to the lack of link-local address:
45 *
46 * Unicast routing exchange:
47 * - RIPng: Impossible.  Uses link-local multicast packet toward ff02::9,
48 *   and link-local addresses as nexthop.
49 * - OSPFv6: Impossible.  OSPFv6 assumes that there's link-local address
50 *   assigned to the link, and makes use of them.  Also, HELLO packets use
51 *   link-local multicast addresses (ff02::5 and ff02::6).
52 * - BGP4+: Maybe.  You can only use global address as nexthop, and global
53 *   address as TCP endpoint address.
54 *
55 * Multicast routing protocols:
56 * - PIM: Hello packet cannot be used to discover adjacent PIM routers.
57 *   Adjacent PIM routers must be configured manually (is it really spec-wise
58 *   correct thing to do?).
59 *
60 * ICMPv6:
61 * - Redirects cannot be used due to the lack of link-local address.
62 *
63 * stf interface does not have, and will not need, a link-local address.
64 * It seems to have no real benefit and does not help the above symptoms much.
65 * Even if we assign link-locals to interface, we cannot really
66 * use link-local unicast/multicast on top of 6to4 cloud (since there's no
67 * encapsulation defined for link-local address), and the above analysis does
68 * not change.  RFC3056 does not mandate the assignment of link-local address
69 * either.
70 *
71 * 6to4 interface has security issues.  Refer to
72 * http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt
73 * for details.  The code tries to filter out some of malicious packets.
74 * Note that there is no way to be 100% secure.
75 */
76
77#include <sys/cdefs.h>
78__KERNEL_RCSID(0, "$NetBSD: if_stf.c,v 1.109 2022/09/03 02:47:59 thorpej Exp $");
79
80#ifdef _KERNEL_OPT
81#include "opt_inet.h"
82#include "stf.h"
83#endif
84
85#ifndef INET6
86	#error "pseudo-device stf requires options INET6"
87#endif
88
89#include <sys/param.h>
90#include <sys/systm.h>
91#include <sys/socket.h>
92#include <sys/sockio.h>
93#include <sys/mbuf.h>
94#include <sys/errno.h>
95#include <sys/ioctl.h>
96#include <sys/proc.h>
97#include <sys/queue.h>
98#include <sys/syslog.h>
99#include <sys/device.h>
100#include <sys/module.h>
101
102#include <sys/cpu.h>
103
104#include <net/if.h>
105#include <net/route.h>
106#include <net/if_types.h>
107#include <net/if_stf.h>
108
109#include <netinet/in.h>
110#include <netinet/in_systm.h>
111#include <netinet/ip.h>
112#include <netinet/ip_var.h>
113#include <netinet/in_var.h>
114
115#include <netinet/ip6.h>
116#include <netinet6/ip6_var.h>
117#include <netinet6/in6_var.h>
118#include <netinet/ip_ecn.h>
119
120#include <netinet/ip_encap.h>
121
122#include <net/bpf.h>
123
124#include "ioconf.h"
125
126#define IN6_IS_ADDR_6TO4(x)	(ntohs((x)->s6_addr16[0]) == 0x2002)
127#define GET_V4(x)	((const struct in_addr *)(&(x)->s6_addr16[1]))
128
129struct stf_softc {
130	struct ifnet	sc_if;	   /* common area */
131	struct route	sc_ro;
132	const struct encaptab *encap_cookie;
133	LIST_ENTRY(stf_softc) sc_list;
134};
135
136static LIST_HEAD(, stf_softc) stf_softc_list;
137
138static int	stf_clone_create(struct if_clone *, int);
139static int	stf_clone_destroy(struct ifnet *);
140
141struct if_clone stf_cloner =
142    IF_CLONE_INITIALIZER("stf", stf_clone_create, stf_clone_destroy);
143
144static int ip_stf_ttl = STF_TTL;
145
146extern struct domain inetdomain;
147
148static const struct encapsw in_stf_encapsw =
149{
150	.encapsw4 = {
151		.pr_input	= in_stf_input,
152		.pr_ctlinput	= NULL,
153	}
154};
155
156static int stf_encapcheck(struct mbuf *, int, int, void *);
157static struct in6_ifaddr *stf_getsrcifa6(struct ifnet *);
158static int stf_output(struct ifnet *, struct mbuf *, const struct sockaddr *,
159	const struct rtentry *);
160static int isrfc1918addr(const struct in_addr *);
161static int stf_checkaddr4(struct stf_softc *, const struct in_addr *,
162	struct ifnet *);
163static int stf_checkaddr6(struct stf_softc *, const struct in6_addr *,
164	struct ifnet *);
165static void stf_rtrequest(int, struct rtentry *, const struct rt_addrinfo *);
166static int stf_ioctl(struct ifnet *, u_long, void *);
167
168/* ARGSUSED */
169void
170stfattach(int count)
171{
172
173	/*
174	 * Nothing to do here, initialization is handled by the
175	 * module initialization code in stfinit() below).
176	 */
177}
178
179static void
180stfinit(void)
181{
182
183	LIST_INIT(&stf_softc_list);
184	if_clone_attach(&stf_cloner);
185}
186
187static int
188stfdetach(void)
189{
190	int error = 0;
191
192	if (!LIST_EMPTY(&stf_softc_list))
193		error = EBUSY;
194
195	if (error == 0)
196		if_clone_detach(&stf_cloner);
197
198	return error;
199}
200
201static int
202stf_clone_create(struct if_clone *ifc, int unit)
203{
204	struct stf_softc *sc;
205	int error;
206
207	sc = malloc(sizeof(struct stf_softc), M_DEVBUF, M_WAIT|M_ZERO);
208	if_initname(&sc->sc_if, ifc->ifc_name, unit);
209
210	error = encap_lock_enter();
211	if (error) {
212		free(sc, M_DEVBUF);
213		return error;
214	}
215
216	if (LIST_FIRST(&stf_softc_list) != NULL) {
217		/* Only one stf interface is allowed. */
218		encap_lock_exit();
219		free(sc, M_DEVBUF);
220		return EEXIST;
221	}
222
223	sc->encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV6,
224	    stf_encapcheck, &in_stf_encapsw, sc);
225	encap_lock_exit();
226	if (sc->encap_cookie == NULL) {
227		printf("%s: unable to attach encap\n", if_name(&sc->sc_if));
228		free(sc, M_DEVBUF);
229		return EIO;	/* XXX */
230	}
231
232	sc->sc_if.if_mtu    = STF_MTU;
233	sc->sc_if.if_flags  = 0;
234	sc->sc_if.if_ioctl  = stf_ioctl;
235	sc->sc_if.if_output = stf_output;
236	sc->sc_if.if_type   = IFT_STF;
237	sc->sc_if.if_dlt    = DLT_NULL;
238	if_attach(&sc->sc_if);
239	if_alloc_sadl(&sc->sc_if);
240	bpf_attach(&sc->sc_if, DLT_NULL, sizeof(u_int));
241	LIST_INSERT_HEAD(&stf_softc_list, sc, sc_list);
242	return 0;
243}
244
245static int
246stf_clone_destroy(struct ifnet *ifp)
247{
248	struct stf_softc *sc = (void *) ifp;
249
250	encap_lock_enter();
251	LIST_REMOVE(sc, sc_list);
252	encap_detach(sc->encap_cookie);
253	encap_lock_exit();
254	bpf_detach(ifp);
255	if_detach(ifp);
256	rtcache_free(&sc->sc_ro);
257	free(sc, M_DEVBUF);
258
259	return 0;
260}
261
262static int
263stf_encapcheck(struct mbuf *m, int off, int proto, void *arg)
264{
265	struct ip ip;
266	struct in6_ifaddr *ia6;
267	struct stf_softc *sc;
268	struct in_addr a, b;
269
270	sc = (struct stf_softc *)arg;
271	if (sc == NULL)
272		return 0;
273
274	if ((sc->sc_if.if_flags & IFF_UP) == 0)
275		return 0;
276
277	/* IFF_LINK0 means "no decapsulation" */
278	if ((sc->sc_if.if_flags & IFF_LINK0) != 0)
279		return 0;
280
281	if (proto != IPPROTO_IPV6)
282		return 0;
283
284	m_copydata(m, 0, sizeof(ip), (void *)&ip);
285
286	if (ip.ip_v != 4)
287		return 0;
288
289	ia6 = stf_getsrcifa6(&sc->sc_if);
290	if (ia6 == NULL)
291		return 0;
292
293	/*
294	 * check if IPv4 dst matches the IPv4 address derived from the
295	 * local 6to4 address.
296	 * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
297	 */
298	if (memcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst,
299	    sizeof(ip.ip_dst)) != 0)
300		return 0;
301
302	/*
303	 * check if IPv4 src matches the IPv4 address derived from the
304	 * local 6to4 address masked by prefixmask.
305	 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
306	 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
307	 */
308	memset(&a, 0, sizeof(a));
309	a.s_addr = GET_V4(&ia6->ia_addr.sin6_addr)->s_addr;
310	a.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
311	b = ip.ip_src;
312	b.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
313	if (a.s_addr != b.s_addr)
314		return 0;
315
316	/* stf interface makes single side match only */
317	return 32;
318}
319
320static struct in6_ifaddr *
321stf_getsrcifa6(struct ifnet *ifp)
322{
323	struct ifaddr *ifa;
324	struct in_ifaddr *ia4;
325	struct sockaddr_in6 *sin6;
326	struct in_addr in;
327	int s;
328
329	s = pserialize_read_enter();
330	IFADDR_READER_FOREACH(ifa, ifp) {
331		if (ifa->ifa_addr->sa_family != AF_INET6)
332			continue;
333		sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
334		if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
335			continue;
336
337		memcpy(&in, GET_V4(&sin6->sin6_addr), sizeof(in));
338		ia4 = in_get_ia(in);
339		if (ia4 == NULL)
340			continue;
341
342		pserialize_read_exit(s);
343		/* TODO NOMPSAFE */
344		return (struct in6_ifaddr *)ifa;
345	}
346	pserialize_read_exit(s);
347
348	return NULL;
349}
350
351static int
352stf_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
353    const struct rtentry *rt0)
354{
355	struct rtentry *rt;
356	struct stf_softc *sc;
357	const struct sockaddr_in6 *dst6;
358	const struct in_addr *in4;
359	uint8_t tos;
360	struct ip *ip;
361	struct ip6_hdr *ip6;
362	struct in6_ifaddr *ia6;
363	union {
364		struct sockaddr		dst;
365		struct sockaddr_in	dst4;
366	} u;
367
368	sc = (struct stf_softc*)ifp;
369	dst6 = (const struct sockaddr_in6 *)dst;
370
371	/* just in case */
372	if ((ifp->if_flags & IFF_UP) == 0) {
373		m_freem(m);
374		return ENETDOWN;
375	}
376
377	/*
378	 * If we don't have an ip4 address that match my inner ip6 address,
379	 * we shouldn't generate output.  Without this check, we'll end up
380	 * using wrong IPv4 source.
381	 */
382	ia6 = stf_getsrcifa6(ifp);
383	if (ia6 == NULL) {
384		m_freem(m);
385		if_statinc(ifp, if_oerrors);
386		return ENETDOWN;
387	}
388
389	if (m->m_len < sizeof(*ip6)) {
390		m = m_pullup(m, sizeof(*ip6));
391		if (m == NULL) {
392			if_statinc(ifp, if_oerrors);
393			return ENOBUFS;
394		}
395	}
396	ip6 = mtod(m, struct ip6_hdr *);
397	tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
398
399	/*
400	 * Pickup the right outer dst addr from the list of candidates.
401	 * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
402	 */
403	if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
404		in4 = GET_V4(&ip6->ip6_dst);
405	else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
406		in4 = GET_V4(&dst6->sin6_addr);
407	else {
408		m_freem(m);
409		if_statinc(ifp, if_oerrors);
410		return ENETUNREACH;
411	}
412
413	bpf_mtap_af(ifp, AF_INET6, m, BPF_D_OUT);
414
415	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
416	if (m && m->m_len < sizeof(struct ip))
417		m = m_pullup(m, sizeof(struct ip));
418	if (m == NULL) {
419		if_statinc(ifp, if_oerrors);
420		return ENOBUFS;
421	}
422	ip = mtod(m, struct ip *);
423
424	memset(ip, 0, sizeof(*ip));
425
426	bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr),
427	    &ip->ip_src, sizeof(ip->ip_src));
428	memcpy(&ip->ip_dst, in4, sizeof(ip->ip_dst));
429	ip->ip_p = IPPROTO_IPV6;
430	ip->ip_ttl = ip_stf_ttl;
431	ip->ip_len = htons(m->m_pkthdr.len);
432	if (ifp->if_flags & IFF_LINK1)
433		ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
434	else
435		ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
436
437	sockaddr_in_init(&u.dst4, &ip->ip_dst, 0);
438	if ((rt = rtcache_lookup(&sc->sc_ro, &u.dst)) == NULL) {
439		m_freem(m);
440		if_statinc(ifp, if_oerrors);
441		return ENETUNREACH;
442	}
443
444	/* If the route constitutes infinite encapsulation, punt. */
445	if (rt->rt_ifp == ifp) {
446		rtcache_unref(rt, &sc->sc_ro);
447		rtcache_free(&sc->sc_ro);
448		m_freem(m);
449		if_statinc(ifp, if_oerrors);
450		return ENETUNREACH;
451	}
452	rtcache_unref(rt, &sc->sc_ro);
453
454	if_statadd2(ifp, if_opackets, 1,
455	    if_obytes, m->m_pkthdr.len - sizeof(struct ip));
456	return ip_output(m, NULL, &sc->sc_ro, 0, NULL, NULL);
457}
458
459static int
460isrfc1918addr(const struct in_addr *in)
461{
462	/*
463	 * returns 1 if private address range:
464	 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
465	 */
466	if ((ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
467	    (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
468	    (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)
469		return 1;
470
471	return 0;
472}
473
474static int
475stf_checkaddr4(struct stf_softc *sc, const struct in_addr *in,
476    struct ifnet *inifp /*incoming interface*/)
477{
478	struct in_ifaddr *ia4;
479
480	/*
481	 * reject packets with the following address:
482	 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
483	 */
484	if (IN_MULTICAST(in->s_addr))
485		return -1;
486	switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
487	case 0: case 127: case 255:
488		return -1;
489	}
490
491	/*
492	 * reject packets with private address range.
493	 * (requirement from RFC3056 section 2 1st paragraph)
494	 */
495	if (isrfc1918addr(in))
496		return -1;
497
498	/*
499	 * reject packet with IPv4 link-local (169.254.0.0/16),
500	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
501	 */
502	if (((ntohl(in->s_addr) & 0xff000000) >> 24) == 169 &&
503	    ((ntohl(in->s_addr) & 0x00ff0000) >> 16) == 254)
504		return -1;
505
506	/*
507	 * reject packets with broadcast
508	 */
509	IN_ADDRLIST_READER_FOREACH(ia4) {
510		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
511			continue;
512		if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
513			return -1;
514	}
515
516	/*
517	 * perform ingress filter
518	 */
519	if (sc && (sc->sc_if.if_flags & IFF_LINK2) == 0 && inifp) {
520		struct sockaddr_in sin;
521		struct rtentry *rt;
522
523		memset(&sin, 0, sizeof(sin));
524		sin.sin_family = AF_INET;
525		sin.sin_len = sizeof(struct sockaddr_in);
526		sin.sin_addr = *in;
527		rt = rtalloc1((struct sockaddr *)&sin, 0);
528		if (!rt || rt->rt_ifp != inifp) {
529#if 0
530			log(LOG_WARNING, "%s: packet from 0x%x dropped "
531			    "due to ingress filter\n", if_name(&sc->sc_if),
532			    (uint32_t)ntohl(sin.sin_addr.s_addr));
533#endif
534			if (rt)
535				rt_unref(rt);
536			return -1;
537		}
538		rt_unref(rt);
539	}
540
541	return 0;
542}
543
544static int
545stf_checkaddr6(struct stf_softc *sc, const struct in6_addr *in6,
546    struct ifnet *inifp /*incoming interface*/)
547{
548
549	/*
550	 * check 6to4 addresses
551	 */
552	if (IN6_IS_ADDR_6TO4(in6))
553		return stf_checkaddr4(sc, GET_V4(in6), inifp);
554
555	/*
556	 * reject anything that look suspicious.  the test is implemented
557	 * in ip6_input too, but we check here as well to
558	 * (1) reject bad packets earlier, and
559	 * (2) to be safe against future ip6_input change.
560	 */
561	if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
562		return -1;
563
564	/*
565	 * reject link-local and site-local unicast
566	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
567	 */
568	if (IN6_IS_ADDR_LINKLOCAL(in6) || IN6_IS_ADDR_SITELOCAL(in6))
569		return -1;
570
571	/*
572	 * reject node-local and link-local multicast
573	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
574	 */
575	if (IN6_IS_ADDR_MC_NODELOCAL(in6) || IN6_IS_ADDR_MC_LINKLOCAL(in6))
576		return -1;
577
578	return 0;
579}
580
581void
582in_stf_input(struct mbuf *m, int off, int proto, void *eparg)
583{
584	int s;
585	struct stf_softc *sc = eparg;
586	struct ip *ip;
587	struct ip6_hdr *ip6;
588	uint8_t otos, itos;
589	struct ifnet *ifp;
590	size_t pktlen;
591
592	KASSERT(sc != NULL);
593
594	if (proto != IPPROTO_IPV6) {
595		m_freem(m);
596		return;
597	}
598
599	ip = mtod(m, struct ip *);
600
601	if ((sc->sc_if.if_flags & IFF_UP) == 0) {
602		m_freem(m);
603		return;
604	}
605
606	ifp = &sc->sc_if;
607
608	/*
609	 * perform sanity check against outer src/dst.
610	 * for source, perform ingress filter as well.
611	 */
612	if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
613	    stf_checkaddr4(sc, &ip->ip_src, m_get_rcvif_NOMPSAFE(m)) < 0) {
614		m_freem(m);
615		return;
616	}
617
618	otos = ip->ip_tos;
619	m_adj(m, off);
620
621	if (m->m_len < sizeof(*ip6)) {
622		m = m_pullup(m, sizeof(*ip6));
623		if (!m)
624			return;
625	}
626	ip6 = mtod(m, struct ip6_hdr *);
627
628	/*
629	 * perform sanity check against inner src/dst.
630	 * for source, perform ingress filter as well.
631	 */
632	if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
633	    stf_checkaddr6(sc, &ip6->ip6_src, m_get_rcvif_NOMPSAFE(m)) < 0) {
634		m_freem(m);
635		return;
636	}
637
638	itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
639	if ((ifp->if_flags & IFF_LINK1) != 0)
640		ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
641	else
642		ip_ecn_egress(ECN_NOCARE, &otos, &itos);
643	ip6->ip6_flow &= ~htonl(0xff << 20);
644	ip6->ip6_flow |= htonl((uint32_t)itos << 20);
645
646	pktlen = m->m_pkthdr.len;
647	m_set_rcvif(m, ifp);
648
649	bpf_mtap_af(ifp, AF_INET6, m, BPF_D_IN);
650
651	/*
652	 * Put the packet to the network layer input queue according to the
653	 * specified address family.
654	 * See net/if_gif.c for possible issues with packet processing
655	 * reorder due to extra queueing.
656	 */
657
658	s = splnet();
659	if (__predict_true(pktq_enqueue(ip6_pktq, m, 0))) {
660		if_statadd2(ifp, if_ipackets, 1, if_ibytes, pktlen);
661	} else {
662		m_freem(m);
663	}
664	splx(s);
665
666	return;
667}
668
669/* ARGSUSED */
670static void
671stf_rtrequest(int cmd, struct rtentry *rt,
672    const struct rt_addrinfo *info)
673{
674	if (rt != NULL) {
675		struct stf_softc *sc;
676
677		sc = LIST_FIRST(&stf_softc_list);
678		rt->rt_rmx.rmx_mtu = (sc != NULL) ? sc->sc_if.if_mtu : STF_MTU;
679	}
680}
681
682static int
683stf_ioctl(struct ifnet *ifp, u_long cmd, void *data)
684{
685	struct ifaddr		*ifa;
686	struct ifreq		*ifr = data;
687	struct sockaddr_in6	*sin6;
688	int			error;
689
690	error = 0;
691	switch (cmd) {
692	case SIOCINITIFADDR:
693		ifa = (struct ifaddr *)data;
694		if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
695			error = EAFNOSUPPORT;
696			break;
697		}
698		sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
699		if (IN6_IS_ADDR_6TO4(&sin6->sin6_addr) &&
700		    !isrfc1918addr(GET_V4(&sin6->sin6_addr))) {
701			ifa->ifa_rtrequest = stf_rtrequest;
702			ifp->if_flags |= IFF_UP;
703		} else
704			error = EINVAL;
705		break;
706
707	case SIOCADDMULTI:
708	case SIOCDELMULTI:
709		if (ifr != NULL &&
710		    ifreq_getaddr(cmd, ifr)->sa_family == AF_INET6)
711			;
712		else
713			error = EAFNOSUPPORT;
714		break;
715
716	case SIOCSIFMTU:
717		if (ifr->ifr_mtu < STF_MTU_MIN || ifr->ifr_mtu > STF_MTU_MAX)
718			return EINVAL;
719		else if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
720			error = 0;
721		break;
722
723	default:
724		error = ifioctl_common(ifp, cmd, data);
725		break;
726	}
727
728	return error;
729}
730
731/*
732 * Module infrastructure
733 */
734#include "if_module.h"
735
736IF_MODULE(MODULE_CLASS_DRIVER, stf, NULL)
737